Molded case industrial-rated circuit breakers such as described within U.S. Pat. No. 4,982,173 employ a pair of separable contacts and an operating mechanism wherein the contacts are restrained from being driven to their open position against the bias of a pair of powerful operating mechanism springs under quiescent circuit current conditions. The digital trip unit within the circuit breaker cover signals the circuit breaker trip actuator to release the contacts and allow them to rapidly move to their open positions upon the occurrence of an overcurrent condition. The mechanical trip test button on the circuit breaker cover allows manual application of a trip force to the operating mechanism which by-passes the trip actuator and articulates the operating mechanism to separate the contacts in the absence of any overcurrent conditions to ensure that the operating mechanism is operating properly.
U.S. Pat. No. 4,814,712 describes an electronic test kit for providing an electrical signal to the trip actuator unit within the circuit breaker cover within higher rated industrial circuit breakers to articulate the operating mechanism to ensure that the trip actuator unit per se is operating properly. The test kit circuit electrically connects with the digital trip unit within the circuit breaker by means of a test jack opening in the rating plug that is contained within a receptacle formed within the circuit breaker cover. The inclusion of a microprocessor within the test kit circuit allows the test kit to perform several additional functions besides activating the trip actuator.
It has been found beneficial to regularly operate the trip actuator to redistribute the lubricating grease employed with the movable components as well as to ensure that the trip actuator is operational. With the lower rated industrial circuit breakers, described earlier, it is not economically feasible to employ the multi-functional test kit unit employed with the higher-rated industrial circuit breakers.
Accordingly, one purpose of this invention is to provide a simple inexpensive test plug that is capable of energizing the trip actuator within lower rated industrial circuit breakers to insure operation and to beneficially redistribute the lubricating grease in the manner described earlier.